Silver halide supersensitized photographic emulsion

ABSTRACT

A SLVER HALIDE PHOTOGRAPHIC EMULSION CONTAINING A COMBINATION OF SENSITIZING DYES OF THE FORMULAE:   1-(R1-OOC-),3,4-(-N(+)(-R2)=C(-CH=C(-R4)-CH=C&lt;(-Z2-(3-W1,   4-W2-1,2-PHENYLENE)-N(-R3)-))-Z1-)BENZENE (X(-))N AND   1-W3,3,4-(-N(+)(-R5)=C(-CH=C(-R7)-CH=C&lt;(-Z4-(4-W4-1,2-   PHENYLENE-N(-R6)-))-Z3-)BENZENE (X(-))N   SPECIFIC COMPOUNDS ARE DISCLOSED HEREINAFTER.

United States Patent 3,705,809 SILVER HALIDE SUPERSENSITIZED PHOTOGRAPHIC EMULSION Yoshiyuki Nakazawa, Yashuharu Nakamura, Haruo Takei, Akira Sato, and Tadashi Ilreda, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Kauagawa, Japan No Drawing. Filed Oct. 20, 1970, Ser. No. 82,537 Claims priority, applicatign Japan, Sept. 26, 1969,

Int. (:1. G03c 1/14 US. Cl. 96124 Claims ABSTRACT OF THE DISCLOSURE A silver halide photographic emulsion containing a combination of sensitizing dyes of the formulae:

Specific compounds are disclosed hereinafter.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the spectral sensitization of silver halide photographic emulsions and, more particularly, to silver halide photographic emulsions which have been super-sensitized by a combination of sensitizers of two dilferent types. In particular, it is concerned with silver halide photographic emulsions having high red sensitivities and spectral sensitization maxima within the region between 625m,u and 665 mp.

DESCRIPTION OF THE PRIOR ART It is well known in the art of silver halide photographic emulsions that the range of the sensitive wave length of a silver halide emulsion is extended and the silver halide emulsion is spectrally sensitized by the addition thereto of a sensitizing dye.

Although sensitization of photo-sensitive materials in a desired spectral range of wave length may usually be attained by the use of a single sensitizing dye, in many cases there are used combinations of two or more sensitizers. Usually, the degree of spectral sensitization brought about by the use of a combination of two or more sensitizers is between those values achieved by the separate use of each sensititzer or even lower than that intermediate value. However, in certain cases, there are obtained remarkably higher degrees of spectral sensitization than those obtained by the sole use of one of the sensitizers. This phenomenon is usually referred to as super sensitization. Even then, the sensitized range of wave length occasionally lies in the middle of those values obtained by the use of the individual sensitizers alone.

In the manufacture of silver halide photographic emulsions, a combination of two or more sensitizers of different types is often used for either sensitization in a desired spectral wave length region as a means for obtaining a 3,705,809 Patented Dec 12, 1972 higher spectral sensititvity than that obtained by the individual use of the sensitizers or controlling the spectrally sensitized wave length region of the emulsion to a certain wave length region.

It has been a significant problem in spectral sensitization techniques to find a combination of sensitizers in the relationship of super sensitization such that there is obtain a higher spectral sensitivity by the use of a combination of sensitizers than that obtained by the use of the individual sensitizers, or that the sensitized wave length region is controlled so as to meet the requirements for the photo-sensitive material.

It is an object of the present invention to provide a silver halide photographic emulsion having a high red sensitivity in the spectrally sensitized wave length region of from 625 mg to 665 mp. by the use of a combination of sensitizers of two difierent types This spectral wave length region is one which is ordinarily adopted in monochromoic photo-sensitive materials and in red-sensitive layers in color photosensitive materials.

SUMMARY OF THE INVENTION The above object of the present invention has been attained by adding to a silver halide photographic emulsion a combination of a sensitizing dye represented by the following Formula I and a sensitizing dye represented by on it N N on 1 R, Rt (11) DESCRIPTION OF THE PREFERRED EMBODIMENTS In the above Formula I, Z and Z which may be the same or dilferent, each represents sulfur or selenium atoms; R represents a hydrogen atom or a lower alkyl group such as methyl or ethyl; W represents a hydrogen atom; W represents a hydrogen atom or a halogen atom such as chlorine or bromine, or a lower alkyl group such as methyl or ethyl, or an alkoxy group such as methoxy or ethoXy group, or an aryl group such as phenyl, or a hydroxyl group; or W and W in combination each represents an atomic group necessary to complete a benzene ring; R and R each represents 'y-sulfopropyl, 'y-SUIfObUtYI, 5-sulfobutyl or vinylmethyl groups; R represents an ethyl group or an aryl group such as phenyl; X represents an acid anion group usually employed in dyes of this type such as chloride, bromide, iodide, perchlorate, thiocyanate, ptoluene sulfonate, benzene sulfonate, methyl sulfate, ethyl sulfate, and the like; and n represents 0 or 1. In the case of an intramolecular salt, n is 0.

In the above Formula II, Z and Z which may be the same or different, each represents sulfur or selenium atoms; W and W which may be the same or different, each represents hydrogen or halogen atoms, or methyl, methoxy, an aryl group such as phenyl, or a hydroxyl group; R represents a methyl or ethyl group, wherein at least one of W and W is other than a hydrogen atom when R-, is a methyl group; R and R which may be the same or different, each represents a lower alkyl group such as methyl or ethyl, a substituted alkyl group such as 'y-sulfopropyl, 'y-sulfobutyl, 6-sulfobutyl, ,B-hydroxyethyl, fi-carboxyethyl or 'ycarboxypropyl, or an allyl group such as vinyl methyl; X represents an anion such as described in X of the Formula I, and n represents to 1. In the case of an intramolecular salt, 11 is O.

The present inventors have found that a high red sensitivity is obtained by the use, in combination, of sensitizing dyes (I) and (II) to eifect an interactive remarkable super sensitization. The sensitizing dyes according to the present invention may be used in combination with other sensitizers having different spectral sensitization ranges, e.g., a sensitizer for enhancing green sensitivity such as pseudo-cyanin.

Specific embodiments of the sensitizing dyes used in the present invention are prepresented by the following formulae, but the present invention should not be limited to these merely illustrative compounds:

[I] max.

A S s CH=OCH HO 0 c H Hm a- CzHs 553 nm. 302

B s s zHs orr=o -on H 0 o c OCH N N/ a y I 559 um above HD3303 02115 300 C s s (EH 011:0- OH- HO 0 0 t (cnalsoa 02m MeOH MP. (C.)

max.

D S Se 0H=OCH= H o 0 0- -o1 N N l I 2115 CzHs 553 nm. 208-210 E s s 2 s -OH=o-CH 0113000 3% CH;

N H 557.5 nm- 0 3 hint 203-296 F S s $2115 CH=C-CH 013300 0 OCH;

N e N I I 661.3 nm. 2H5 C2H5 295-296 G s s CH=-CH 011300 6 OH 559 nm. amisol (52m 238-240 MeOH M.P. (C) max.

( HQaSOZ DaS 3 HOOO Cl l CH1-CH=CH Se Se i I -CH=CCH CH; N N

ormasoa OH; OH:

s s (5) (5H3 CH=CCH OHIO A\ -OCH3 N N 1 CzH5 CgH5 Se Se -ou=b-on HO X -OH H e N I (j: 02H: 2H:

s s (7) 2 a /CH=CCH o1 -o1 \t \N/ (2211. onmon s CH3 /-on=bon on; on, i i Er N/ ((BHQZOH (AHQQOH 2 5 /-OH=CCH\ l n 11 \3 III/ enmso. (CH2)4SO3H /-oH=b-oH c11 i l 0111. (cumsot 11 s CHI /on=b-on I 01 01 \g III/ bnzcnzooo CH2CH2COOH 02m -cH=o-on= 01 e/ 9 -01 N N onzon=orn drncn=om The sensitizing dyes (I) and (II) may be synthesized by known processes. For instance, synthesis may be attained without difficulty by referring to U.S. Pat. Nos. 2,503,776 and 2,647,051.

The synthesis of sensitizing dye IC, as listed above, is illustrated hereinafter as a representative example of a typical synthesis.

A mixture of 1.5 g. of -phenyl-3-ethyl-2-thiopropionylmethylene-benzothiazoline and 1.5 g. of methyl paratoluenesulfonate is heated at 110 C. for 2 hours and, after cooling, the reaction mixture is washed with ethyl ether. 1.5 g. of anhydro-S-carboxy-2-rnethyl-3-('y-sulfopl'opyl)- benzothiazolium hydroxide, dissolved in 160 ml. of ethanol, is then added to the reaction product, refluxed for 3 hours in the presence of 5 ml. of triethylamine and freed from solvent by distillation. The residue is crystallized by treatment with ethyl ether. The crystals are recovered by filtration, thoroughly washed with acetone and recrystallized from a methanol-chloroform mixture to obtain 1.1 g. of a dye having a M.P. of 287 C. and a mat.

of 559 nm.

The other sensitizing dyes of the present invention may be synthesized by methods similar to that described above.

The spectral sensitization process of the present invention is elfective for the spectral sensitization of gelatino silver halide emulsions. In the process, emulsions containing a synthetic or natural hydrophilic resinous material other than gelatin, such as agar agar, Water-soluble cellulose derivatives, colloidion or polyvinyl alcohol, may also be sufficiently sensitized.

The photographic emulsion suitable used in the present invention includes silver iodobromide, silver chlorobromide and like mixed silver halide emulsions.

The spectrally sensitized photographic emulsion of the present invention may be prepared by incorporating the sensitizing dyes (I) and (II) in a photographic emulsion in a conventional manner. In practice, it is usual to add a solution of the dyes to an emulsion in a suitable solvent, such as methanol or ethanol. The molar ratio of sensitizing dye (I) to dye (II) may be varied in a wide range of from 9:1 to 1:9, according to the desired effects.

Generally, from 0.009 to 0.14 mole of each of dyes (I) and (II) may be added to each 1 kg. of emulsion.

The photographic emulsion of the present invention may also be subjected to a hyper-sensitization by known processes.

In the preparation of the photographic emulsion of the present invention there may also be incorporated in the emulsion conventional additives such as, e.g., a sensitizer, a stabilizer, a toner, a hardener, a surface active agent, an anti-fogging agent, a plasticizer, a developing promoter, a color developer and an optical whitening agent.

The photographic emulsion of the present invention may be applied to a suitable support such as, e.g., sheet glass, a film of a cellulose derivative, a film of a synthetic resin or baryta paper in a conventional manner.

The present invention will now be illustrated in more detail by the following examples, which are not intended to be limiting in nature.

EXAMPLES To separate portions of a silver iodobromide emulsion in which the molar ratio of AgI to AgBr was 7:93, and Where the emulsion contained about 25.4 g. of silver per 1 kg. of emulsion, there was added a sensitizing dye (I) alone, a sensitizing dye (II) alone or a combination of (I) and (II) to form sensitized silver halide emulsions. The emulsions were separately applied to triacetylcellulose film bases and, after drying, exposed to a light of day light color corresponding to a color temperature of 5,400 K. through a Fuji filter No. 7 (trademark; (a red filter transmitting light having a Wave length of 580 nm or more) supplied by Fuji Photo Film Co., Ltd., and then developed using a developing solution of the formulation as indicated in Table 1.

Water to make 1 liter.

In the following Table 2 are shown the spectral sensitivity and sensitization maxima obtained by using the sensitizing dye (I) alone, as described above. In the following Table 3 are indicated those obtained by using the sensitizer dye (II) alone, as described above. In Table 4 are indicated those obtained by combinations of representative sensitizing dyes (I) and (H).

TABLE 2 Amount of Sensitidye added zation 5 mol/kg. maxima Red sensi- Dye number emulsion) Emulsion (nm.) tivities A- 8 AgBr/I 643 230 B s AgBr/I 650 370 0 s AgBr/I 625 100 D 6 AgBr/I 652 260 10 E- s AgBr/I 647 300 F- 4 AgBr/I 643 160 G s AgBr/I 650 250 H 6 AgBr/I 628 130 I- 4 AgBr/I 650 260 J 8 AgBr/I 654 82 K s AgBr/I 656 160 L s AgBr/I 646 72 The red sensitivity is indicated as the specific sensitivity regarding the red sensitivity of sensitizing dye C upon exposure through a F1111 filter No. 7 (red filter) as 100.

TABLE 3 Amount of dye added Sensiti- 10 Incl/kg, zationrnax- Red sensi- Dye number emulsion) Emulsion ima(nm.) tivities s AgBr/I 640-660 126 s AgBr/ 662 250 s AgBr/I 660 250 6 AgBr/I 635 145 8 AgBr/I 632 230 6 AgBr/I 680 160 s AgBl 660 270 6 AgBr/I 590-600 44 s AgBr/ 638 130 s .AgBr/I 600-610 74 6 AgBr/ 658 260 8 AgBr/I 660 160 The red sensitivity is indicated as the specific sensitivity regarding the red sensitivity of sensitizing dye C upon exposure through a F1111 filter No. 7 (red filter) as 100.

TABLE4 Amount of Sensitidye added zation Example Dye (10 moi/k msixima Red sensi- No. Number emulsion Emulsion (nm.) m tivities A s AgBr/I 643 230 2 s AgBr/I 662 250 6 s AgBr/I 632 230 1 n+2 4+3 AgBr/I 656 370 A+5 6+2 AgBr/I 643 370 B s AgBr/I 650 370 0 s AgBr/I 638 130 2 B+9 6+2 AgBr/I 648 470 C 8 AgBr/I 625 100 J 8 AgBr/I 654 82 3 8 AgBr/I 660 250 59 3 0+3 2+6 AgBr/I 655 310 J+3 2+6 AgBr/I 660 300 D 6 AgBr/I 652 250 2 s AgBr/I 662 250 4 D+2 4+3 AgBr/I 658 640 E a AgBr/I 647 390 4 6 AgBr/I 635 146 7 s AgBr/I 660 270 5 n+4 6+2 AgBr/I 646 470 E+7 6+2 AgBr/I 660 600 F 4 AgBr/I 643 150 1 8 AgBr/I 640-660 126 6 6 AgBr/I 680 160 6 F+1 3+3 AgBr/I 648 330 F+6 6+2 AgBr/I 664 360 60 ,G 8 AgBr/I 660 260 3 s AgBr/I 660 250 s 6 AgBr/I 690-600 44 12 s AgBr/I 660 160 G+3 2+6 AgBr/I 660 640 77 G+8 7+1 AgBr/I 660 320 G+12 6+2 AgBr/I 658 310 H 6 AgBr/I 628 130 10 a AgBr/I 690610 74 s H+10 6+2 AgBr/I 628 220 I 4 AgBr/I 650 260 II 6 AgBr/I 658 260 9 I+1i 2+6 AgBr/I 666 320 a s AgBr/I 660 260 K a AgBr/I 656 160 L 8 AgBr/I 645 72 m 3+K 6+2 AgBr/I 660 300 3+L 6+2 AgBr/I 660 200 The red sensitivity is indicated as the specific or relative sensitivity calculated by regarding the specific or 75 1 it; (I)

Z a Z 4 1 CH=( 1-CH= W4 i or N wherein, in Formula I, Z and Z which may be the same or different, each represents a sulfur or selenium atom; R represents a hydrogen atom or a lower alkyl group; W represents a hydrogen atom and W represents a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxy group, an aryl group or a hydroxyl group, or in combination W and W represent atomic groups necessary to complete a benzene ring; R and R each represent an ethyl, n-propyl, -sulfopropyl, 'y-sulfobutyl, 6- sulfobutyl or vinylmethyl group; R represents an ethyl or aryl group; X represents an anion, and n represents 0 or 1, where, in the case of an intramolecular salt, n=0; and, in Formula II, 2;; and Z which may be the same or different, each represent a sulfur or selenium atom; W and W which may be the same or diiferent, each represents a hydrogen atom, halogen atom, methyl, methoxy, aryl or hydroxyl group; R represents a methyl or ethyl group, wherein at least one of W and W is other than hydrogen when R, is a methyl group; R and R represent lower alkyl, a substituted lower alkyl from the group consisting of sulfoalkyl, carboxyalkyl or hydroxyalkyl, or an allyl group; X represents an anion; and n represents 0 or 1 and, in the case of an intramolecular salt, n=0.

2. A silver halide photographic emulsion as claimed in claim 1 wherein the lower alkyl group in R R R and W is an alkyl group having from 1 to 4 carbon atoms.

3. A silver halide photographic emulsion containing a combination of at least one sensitizing dye selected from the group consisting of consisting of,

S S and at least one sensitizing dye selected from the group 02H! -CH=I-CH= 11000 a; N N/ 1 1 CH S\ I -on=h-on{ 01 Cl \3 N/ hnzornc $11,011.00 OH and 4. The silver halide photographic emulsion as claimed in claim 1 wherein the molar ratio of the sensitizing dye of Formula I to the sensitizing dye of Formula II is within the range of from 1:9 to 9: 1.

5. A photographic light-sensitive element comprising a support having thereon at least one layer containing the silver halide emulsion as claimed in claim 1.

6. The silver halide photographic emulsion as claimed in claim 4 having a high red sensitivity in the spectrally sensitized wavelength region of from 625 m to 665 m wherein from 0.009 to 0.14 mol of each of the dyes of Formula I and II is added to 1 kg. of emulsion.

7. The photographic light-sensitive element as claimed in claim 5 wherein the molar ratio of the sensitizing dye 12 of Formula I to the sensitizing dye of Formula H is within the range of from 1:9 to 9:1.

8. The photographic light-sensitive element as claimed in claim 5 having a high red sensitivity in the spectrally sensitized wavelength region of from 625 mp. to 665 mp wherein from 0.009 to 0.14 mol of each of the dyes of Formula I and II is added to 1 kg. of emulsion.

9. The silver halide photographic emulsion as claimed in claim 6 wherein Z and Z are both sulfur or one of Z and Z is sulfur and the other is selenium, and wherein Z, and Z, are both sulfur or wherein Z and Z; are both selenium.

10. A photographic light-sensitive element as claimed in claim 9 wherein Z; and Z, are both sulfur or one of Z and Z is sulfur and the other is selenium, and wherein Z; and Z, are both sulfur or wherein Z and Z; are both selenium.

References Cited UNITED STATES PATENTS 2,647,050 7/1953 Firestine 96-l37 2,647,051 7/1953 Vinton et a1. 96l37 3,527,641 9/1970 Nakazawa et al. 96-124 3,573,920 4/1971 Hiller 96-124 J. TRAVIS BROWN, Primary Examiner US. Cl. XJR. 96-137, 142 

